Transformer for high-frequency currents.



G. MARCONI & w. s. ENTWISTLE,

TRANSFORMER FOR HIGH FREQUENCY CURRENTS.

APPLICATION FILED MAY 23, I914.

1,246,973. Patented Nov. 20,1917.

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G. MARCONI & W. S. ENTWISTLE. TRANSFORMER FOR HIGH FREQUENCY CURRENTS.APPLRCATION FILED MAY 23. 1914.

1,246,973. Patented Nov. 20, 1917.

2 SHEETS-SHEET 2.

'fgai UNITED STATES PATENT OFFICE.

G'U'GLIELMO MARGONI AND WILLIAM SNOWLEY ENTWISTLE, OF LONDON, ENGLAND,ASSIGNORS T0 MARCONI WIRELESS TELEGRAPH COMPANY OF AMERICA, OF NEW YORK,N. Y., A CORPORATION OF NEW JERSEY. I

TRANSFORMER FOR HIGH-FREQUENCY OURRENTS.

Specification of Letters Patent.

Patented Nov. 20, 191 '7.

Application filed May 23, 1914. Serial No. 840,424.

To all whom it may concern Be it known that we, GUGLIELMO MAR- CONI, asubject of the King of Italy, and VVILLIAM SNOWLEY ENTWISTLE, a subjectof the King of Great Britain, both residing at Marconi House, Strand,London, England, have invented new and useful Improvements inTransformers for High-Frequency Currents, of which the followingis aspecification. 4

This invention relates to transformers for use with high frequency, thatis radio frequency, electric impulses and the object is to provide atransformer for the high power radio signaling apparatus used fortransoceanic signaling.

It is well known that high frequency alternations are confined to thesurface of the.

conductor and that a stranded conductoris best adapted for use with suchcurrents. The primary coil here shown and described is five or six ormore feet in diameter and is associated with a-secondary coil locatedinside-the ring or circle formed by the primary or it may be thesecondary is outside the primary or it may be at one side of saidprimary. We use 'a non-magnetic core and the stranded conductor, aseries of insulated strands, is helically disposed, preferably one layerand one single, helical convolution extending from end to end of thecore. The

core is divided at one point, like a split ring, thus afi'ording meansfor connecting the stran (led-conductors to separated conducting platesat the terminals of the conductors, said conductors being thus connectedelectrically in parallel. The advantage of this helical arrangement isthat no matter where the secondary coil is located with respect to theprimary the inductive action of the exposed surface of one coil on theother coil is equal for each and every strand on the con ductor formedof the series of strands.

Figure 1'. is an edge view and Fig. 2 a side view of a large split rmgprimary with a single convolution made according to this in vention.Fig. 3 is a section on the line 3-3, Fig. 2. Fig. 4 is an edge view andFig. 5 a side view of amultiple arrangement of the primary coil. Thescale of Figs. 4 and 5' is somewhat smaller than that of Figs. 1 to 3.In the examples shown the rings are about five feet in diameter and onefoot thick, butthese dimensions may be varied very widely according tocircumstances.

Each ring has a non-conducting core a preferably built'up (as shown insection at Fig. 3) of boards glued together and connected by woodenpins. 6 are the insulated.

conductors, the ends of which are connected to terminal plates 0. Theseconductors are merely indicated diagrammatically; in practice they toucheach other and there are about one hundred and fifty of them, eachconsisting of a number of insulated wires stranded or interwoventogether into a cable in the manner crmmonly adopted in conductors ofhigh frequency currents.

The drawings show the conductors only once twisted around eachconvolution of the ring and this is generally the best arrangement,'butthey may be twisted twice or more around it but fractions of turnsshould be avoided. I

The rings are preferably of circular section as shown.

What we claim is 1. In a high frequency current transformer a primarycoil having a non-magnetic core in the form of a divided ring ofcircular cross-section, a terminal at each end of the core and a helicalconductor consistmary coil having a core of non-magnetic material,divided at one point, with a series of insulated conductors laid in.parallel order on said core and electrically connected in parallel atthe point of division of said core.

4. In a high frequency transformer a primary coil of laminatednon-magnetic'ma terial in the form of a divided ring, circular incross-section, and a series of insulated conductor strands helicallydisposed in parallel upon said ring.

5. In ahigh frequency transformer a primary coil consisting of a splitring of nonmagnetic material and a single layer of electrical conductorshelically disposed upon .said ring and divided at the ends of the splitring.

6. In a transformer a primary coil having a non-magnetic split ring coreand a single layer of insulated conducting strands helically disposed onsaid core.

7. In a transformer a primary coil having a non-magnetic split ringcorecircular in cross section and a layer composed of individuallyinsulated conducting strands helically disposed thereon.

8. In a transformer, a primary coil having a non-magnetic split ringcore, circular in cross section, With a series of insulated strandshelically disposed in one layer and in one convolution extending fromone end of said ring to the other.

9. In a transformer a primary having a split ring core of laminatednon-magnetic material and a layer of stranded conductors helicallydisposed.

10. In a transformer a primary having a in parallel and having freeterminals coincident witl1 tl1e terminals of said core.

11. In a high frequency transformer, 21

primary coil consisting of a split ring of non-magnetio material navinga terminal at each end thereof, and a single layer of electricalconductors helically disposed upon said ring and connected to saidterminals.

12. In a transformer, a primary coil having a non-magnetic splitringcore with a series of insulated strands helically disposed in onelayer and in one convolution, extending from one end of said ring to theother.

13. In a high frequency transformer, a primary coil provided withasubstantially circular core having two free ends, and with a series ofinsulated conductors laid in parallel order on said core andelectrically connected in parallel at said free ends.

' GU LIELMO MARCONI.

i LLIAM SNOWLEY ENTWISTLE. lVitnesses:

W. L. MCEWEN, J. ST. VINCENT PLETTS.

